It is known from German patent document 4,036,634 of Fleischer, 4,229,030 of Worwag, 196 14 624 of Dilger, and 197 06 166 of Worwag as well as U.S. Pat. Nos. 4,776,059, 5,249,333, 5,293,665, and 5,920,939 to provide a power nozzle for a vacuum cleaner that has a driven brush serving to raise dirt and dust out of the object being vacuumed. Such a nozzle has a housing forming a turbine compartment and a brush compartment and having opening into the turbine compartment an outlet adapted for connection to a fan input and a slot opening into the brush compartment. The brush is rotatable in the brush compartment and has bristles projecting from the slot. A turbine in the turbine compartment is oriented such that air flow from the slot to the outlet rotates the turbine and some sort of transmission or link is provided for coupling the turbine to the brush for rotating the brush.
Rather than just having the brush rotating full time, whenever suction is applied to the outlet connection, it is known to provide some sort of element which is actuated to arrest rotation of the brush on displacement of the button into the inner position. This element normally protrudes from the bottom of the nozzle adjacent the slot so that, when the nozzle is pressed against a surface to be power vacuumed, the brush is automatically set in rotation.
The disadvantage of this system is that the brush will operate whenever the nozzle is set down right side up, potentially wearing itself out or wearing a hole in whatever it is left sitting on. Since these nozzles are mainly intended for cleaning floors, such operation is fairly logical, but if the nozzle is to be used on upholstery or drapes this type of operation can cause a problem. In addition if the user does not want to use the power-brushing feature, there is no way to disable it, for instance when vacuuming something delicate like drapes.